Effect of cellulase-producing bacteria on the metabolic activities and functional diversity of bacterial communities in Chinese liquor fermenting grains

Abstract

To study the roles of cellulase-producing bacteria in the fermentation of Chinese liquor fermenting grains, a strain of cellulase-producing bacteria was added into the fermenting grains at different levels, and the substrate utilization was profiled to evaluate the bacterial communities' functional diversity in fermenting grains during fermentation. The results showed that, when the addition level of the cellulase-producing bacteria was at or below 102 cfu/g, the average well colour development (AWCD590nm) of the fermenting grains was not affected significantly. When the addition level was more than 104 cfu/g, the average well colour development (AWCD590nm) of the fermenting grains increased significantly, and the maximum AWCD590nm was obtained when the addition was 106 cfu/g. The diversity index analysis showed that the addition of the cellulase-producing bacteria helped to increase the uniformity of bacterial communities in fermenting grains significantly, while the richness and dominance of the microbial communities were not affected.